8Q0N

HACE1 in complex with RAC1 Q61L

This is a non-PDB format compatible entry.

Summary for 8Q0N

• Entry DOI: 10.2210/pdb8q0n/pdb
• Related: 8PWL
• EMDB information: 18056
• Descriptor: E3 ubiquitin-protein ligase HACE1, Ras-related C3 botulinum toxin substrate 1, iodoacetic acid, ... (4 entities in total)
• Functional Keywords: e3, ubiquitin ligase, small gtpase, crosslink, sia, ligase
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 2
• Total formula weight: 124409.46

Authors

Wolter, M.,Duering, J.,Dienemann, C.,Lorenz, S. (deposition date: 2023-07-28, release date: 2024-01-10, Last modification date: 2024-10-23)

Primary citation

During, J.,Wolter, M.,Toplak, J.J.,Torres, C.,Dybkov, O.,Fokkens, T.J.,Bohnsack, K.E.,Urlaub, H.,Steinchen, W.,Dienemann, C.,Lorenz, S.
Structural mechanisms of autoinhibition and substrate recognition by the ubiquitin ligase HACE1.
Nat.Struct.Mol.Biol., 31:364-377, 2024

PubMed Abstract: Ubiquitin ligases (E3s) are pivotal specificity determinants in the ubiquitin system by selecting substrates and decorating them with distinct ubiquitin signals. However, structure determination of the underlying, specific E3-substrate complexes has proven challenging owing to their transient nature. In particular, it is incompletely understood how members of the catalytic cysteine-driven class of HECT-type ligases (HECTs) position substrate proteins for modification. Here, we report a cryogenic electron microscopy (cryo-EM) structure of the full-length human HECT HACE1, along with solution-based conformational analyses by small-angle X-ray scattering and hydrogen-deuterium exchange mass spectrometry. Structure-based functional analyses in vitro and in cells reveal that the activity of HACE1 is stringently regulated by dimerization-induced autoinhibition. The inhibition occurs at the first step of the catalytic cycle and is thus substrate-independent. We use mechanism-based chemical crosslinking to reconstitute a complex of activated, monomeric HACE1 with its major substrate, RAC1, determine its structure by cryo-EM and validate the binding mode by solution-based analyses. Our findings explain how HACE1 achieves selectivity in ubiquitinating the active, GTP-loaded state of RAC1 and establish a framework for interpreting mutational alterations of the HACE1-RAC1 interplay in disease. More broadly, this work illuminates central unexplored aspects in the architecture, conformational dynamics, regulation and specificity of full-length HECTs.

PubMed: 38332367
DOI: 10.1038/s41594-023-01203-4

Experimental method

ELECTRON MICROSCOPY (4.2 Å)